1. Field of the Invention
The present invention relates to an undeveloped photographic film which is to be developed by a film developing apparatus of a leader-convey type.
2. Discussion of the Related Art
Generally, when a photographic film is developed by an automatic film developing apparatus of the leader-convey type, the undeveloped photographic film is connected with a flexible leader and is conveyed after the leader along a film conveyance path of a developing device.
The leader and the photographic film are generally connected by adhering a splice tape thereto. However, this requires a splice gauge in order to connect the photographic film in a specified position of the leader. Further, when the photographic film is separated by cutting after development, the splice tape remains on the leader making it necessary to peel the splice tape back from the leader so that the leader can be reused. Thus, this type of connection is very cumbersome.
Further, this connection is not economical because the splice tape cannot be reused.
In order to solve such a problem, a film connecting construction of a film-hook type in which an engaging piece is provided on a leader and an engaging hole is formed at the leading end of a photographic film has been proposed. In this construction the engaging piece is engaged with the engaging hole.
In the automatic film developing apparatus of a leader-convey type, the film is pulled by the leader that is conveyed before it. Accordingly, a resistance produced during the movement of the film acts on the connecting portion with the leader. In the film connecting construction of a film-hook type, a pulling force acts on the engaging hole formed at the leading end of the film. Accordingly, if the film is caught during the conveyance, the film may be torn at the engaging hole. Particularly, since a 135 film taken up into a cartridge is thinner than an APS film, it is likely to be torn if the film catches in the processing.